A boiler service can help ensure your boiler and central heating system are running as smoothly and efficiently as possible. The service usually takes about an hour (1 ½ hours for oil), though this will depend on the appliance. During the service, a professional Gas Safe or OFTEC engineer will follow a comprehensive boiler service checklist to make sure everything has been checked and is working well.

Our qualified Gas Safe/ OFTEC engineers have the expertise needed to provide you with a thorough boiler service. Conducting various tests, we aim to ensure that your boiler is functioning safely, effectively and efficiently.

For new systems, a modern high efficiency boiler with advanced compensation controls will make a tremendous difference in performance, efficiency and overall comfort! Most existing boilers can be upgraded with advanced compensation controls to replace standard on/off controls. Again this will make a huge difference in both efficiency and comfort levels.

Condensing boilers use latent heat from the flue gases to improve overall boiler efficiency. Instead of discarding the hot flue gases straight to atmosphere, the hot gases are recycled to make use of the heat. As the water vapour condenses, it produces the by-product condensate which is discarded to waste. Since April 2005, building regulations stipulate that all new domestic boilers should be condensing boilers.

It is extremely important to have the correct sized boiler. This needs to be matched to the heat loss of the property, together with the size and type of heat emitters (radiators or underfloor heating). If it is undersized, the property may be cold in the winter. If it is over sized, it will be inefficient, and the boiler will continuously cycle on and off. In the UK, most properties have an oversized boiler!

Power flushing is the process by which heating systems are forcibly cleansed using water at high velocity, but using low pressure so that no physical damage is caused to the system. The process can be made even more effective with the addition of powerful cleansing and mobilising agents to breakdown the sludge and remove limescale build up.

A power flush is often carried out to restore a heating system to optimum efficiency. It can remove blockages, sludge, limescale and corrosion deposits. When carried out properly and thoroughly, radiators heat up more quickly (without cold spots) and the whole heating system will run more efficiently and quietly.
A clean and protected system also improves the boiler efficiency, helps the pump and diverter valves to last much longer and reduces corrosion.

A noisy plumbing system may be caused by various reasons, but often attributable to the water velocity running through the pipes. By reducing the velocity you can reduce the noise. It may be that the system was poorly designed with undersized pipes, or that faulty components (stop valves, ball valves, etc) need to be replaced or adjusted as necessary.

As the developed world grapples with decarbonisation there is an increasing noise around heat pumps. The reality is that heat pumps, due to a wide variety of reasons, are only suitable for around 20% of the UK’s existing housing stock without major investment in building fabric improvement (for example: window replacement, wall insulation, roof space insulation, radiator upsizing and pipework replacement).

A hybrid heating system is a fossil or hydrogen fuel boiler working in conjunction with a heat pump. By combining these two forms of heat generation and using clever engineering and technology the best of the two systems can be realised with the potential to reduce carbon emissions by up to 87%.

An unvented hot water storage cylinder is a device for storing hot water for later use. An unvented cylinder (as opposed to a vented cylinder) is one that stores water at mains pressure. An unvented hot water cylinder delivers hot water at mains pressure. As a result of these pressures there are specific regulations and qualifications (G3) that apply to the installation and maintenance of unvented hot water systems. It is important that unvented cylinders are serviced at regular intervals in accordance with manufacturers instructions.

Wet central heating systems are either 'open vented' or 'sealed'. A sealed heating system is sealed to the atmosphere: it’s a closed circuit, and is pressurised to the designed pressure (typically, 1 bar). As the preferred choice, a sealed system is more efficient and less likely to suffer from air locks, air ingress, sludge and corrosion.

Smart heating controls, or smart thermostats, enable a heating system to be controlled remotely via a smart phone, tablet or desktop computer (PC). This enables more convenient and efficient control of the heating system.

The use of inhibitors is greatly misunderstood throughout the UK, and may well have a negative affect on the heating system, and cause more harm than good!

Inhibitors (e.g. Fernox F1, Sentinel 100, Adey MC1) are used to reduce corrosion, but it’s just not that simple; there is no single-solution for all systems. There are many factors to consider, for example, conductivity, PH (acidity/alkalinity), hardness, etc.

All this depends on the make-up of the system, whether the boiler has an aluminium, copper or stainless steel heat exchanger, steel radiators, underfloor heating, or both, sealed or open vent system, etc.

Wet central heating systems are either open vented or sealed. The older open vent systems are so called as they are vented to the atmosphere. A small (F&E) feed and expansion tank is used to fill and pressurise the heating system. As the name suggests, the F&E tank also accommodates the expansion from the heating system. Open vented systems are far more prone to corrosion as they allow oxygen to be absorbed into the system water which then passes through steel radiators and creates iron oxide or magnetite (AKA sludge).

Simple answer is yes! All wet heating systems corrode; the expertise is to analyse and understand the chemical process, and ultimately reduce the corrosion process as much as possible. Corrosion affects efficiency and performance. Badly designed or poorly maintained heating systems will degrade over time; even in as little as a few weeks! See our section on corrosion in heating systems.

Sludge, caused by corrosion within a heating system, is due to poor system design or poor maintenance. Sludge will reduce performance and efficiency, and the root cause should be investigated as soon as possible.

A magnetic filter helps maintain a clean heating system. It filters out both magnetic (steel, rust) and non-magnetic (dirt) debris from the heating system. It also offers protection to the boiler heat exchanger. Flush Heating & Plumbing have always recommended installing a good quality filter; indeed Worcester Bosch now offer an extended warranty if the boiler is installed with a filter. Installation of a magnetic system filter with a new boiler is now also part of the building regulations Part L.

This really depends on the property, your lifestyle, amount of insulation, the thermal mass, the type of heating system, and the heating controls.

Certainly with any of our new systems, the heating is effectively on 24/7, and the desired temperature will determine whether the boiler actually needs to fire. For example, you may set the desired temperature to 21C during the day and 16C at night. If the property is well insulated and the overnight temperature remains above 16C, then the boiler will not fire.

Modern heating controls enable far superior control over time and temperature settings when compared to a standard programmer with room stat.

A weather compensation heating system modulates the boiler according to the outdoor temperature.

When the weather is very cold, the boiler will increase the flow temperature (hotter radiators). Conversely, if the weather is mild, the boiler will run at lower temperatures. The outdoor temperature is monitored via an outdoor sensor, or an online weather station. With this advance information, the boiler quickly reacts to external temperature changes before it affects the indoor temperature.

A heating system controlled with weather compensation is much more efficient than on using basic room thermostats and standard on-off controls.

If some radiators don’t get hot, it may be that the system needs balancing. Hot water follows the path of least resistance, and may bypass some areas of the heating system, if not correctly balanced. This may be due to a blockage in the pipework or simply that other radiators are taking all the heat! Reducing flow to hotter radiators may encourage other areas of the system to heat up. This tends to be an iterative process by adjusting the lock shield valves on each radiator. It should result in all radiators warming up at a similar rate.

Thermostatic valves control the temperature of an individual room or area. They are fitted to your radiators (one per radiator) and have an internal thermostat to enable temperature control to individual rooms around your home.

This usually means trapped air at the top of your radiator. Bleeding the radiator should release the air and cure the problem. If this doesn’t help we suggest that you have your central heating checked by an expert, in case there are any underlying system problems.

Assuming the radiator has reached operating temperature, this usually implies there is a build up of sludge at the bottom of your radiator. In this situation the heating system will be operating inefficiently and should be attended to, sooner rather than later. We would advise that the heating system is checked over in case there are underlying system problems.

This usually means that your central heating system is incorrectly balanced. This results in the heating water not flowing evenly to each radiator, and it is best to have it checked by your local heating engineer.